i'll go give that a try after lunch, i'm really tempted to take the valve cover off and take alook , it will not hurt to do that if that clatter is from a pushrod that is loose or a rocker arm is not adjusted/ locknut came loose. i should be able to get some sort of cough or sputter from this motor. i have overhauled several chevy smallblocks/mopar and ford. also i have pulled inframes on cat 3406b/c models and one seris 60 detroit diesel engines. so i'll finish lunch and go back outside and have some fun just wish it was warmer than 37 degrees out.